In the compiled Bollinger Bands indicator that comes with MetaTrader, in the main dialog box for the indicator under "Parameters" tab, change the color to NONE, click on "Levels" tab and add the deviations desired (ex: 2 and -2) and click "Ok".

You can also use this to configure the Bollinger Bands Indicator as a "MOBO" Bands indicator, by setting the "Period" to 10 and (click "Levels" Tab) and set deviations to .8 and -.8 -- it works very well.